The day his 15-year-old son left home will be forever seared into Yuan Cheng's memory. The family woke while it was still dark and his wife prepared breakfast. At daybreak, he readied his motorcycle to take Yuan Xueyu to the highway, an hour's ride away along a bumpy country road, to catch the bus to Beijing with friends then a train to Zhengzhou, Henan province, and a job on a construction site.
Just as he was about to leave, Xuejing, his six-year-old sister, ran out of the house and begged Xueyu not to go. The boy walked back and whispered something into her ear before jumping onto the back of his father's motorcycle.
Two weeks later one of his friends telephoned. Xueyu had been asked to take a tool to another worker and never came back. That was more than two years ago, in March 2007.
The boy's whereabouts remain unknown but Yuan, or Lao (Old) Yuan, as he is known by his friends, fears his son is one of the countless young Chinese who have been kidnapped and forced to work in the illegal brick factories that dot the countryside - ominously known as black kilns.
Yuan, 41, headed for Zhengzhou the day after receiving the phone call. He went to the police, who told him he had to wait 24 hours before filing a missing person's report. Unable to sit and wait, Yuan went to the site to search for clues that might point to his son's location. He found nothing.
The next day, the police had little hope to offer Yuan. A few days earlier, at the same site, someone had put a hood over the head of another boy from Yuan's village and dragged him at knifepoint into a waiting van - he managed to escape shortly after, when the vehicle stopped to pick up more young men. The police had not even bothered to talk to the boy.
Three months after Yuan Xueyu disappeared, his father received a phone call from a man who said he was in Shanxi province, claimed he had his son and wanted a ransom of 50,000 yuan (HK$57,000). Suspicious, he asked to speak to the boy. A voice came onto the phone for a few seconds and blurted out, 'Pa, rescue me.'